A body of mass 0.1kg falling freely under gravity takes 10 second to reach the ground. Calculate kinetic energy & potential energy of the body, when the body has travelled for 6 seconds.

Question: A body of mass 0.1kg falling freely under gravity takes 10 second to reach the ground. Calculate kinetic energy & potential energy of the body, when the body has travelled for 6 seconds.

Given: m=0.1kgm,u=0,

t=6sec, a=g

∴ From v=u+at

             v=0+9.8∗6

             v=58.8m/s 

 

∴ kinetic energy of the body, when the body has travelled for 6 seconds, is

K.E =  (1/2)mv^2

K.E = 172.9J

To Find Potential Energy (PE):

Distance travelled by the body in 10 sec, is

S  =ut+(1/2) gt^2

      =490m

Distance travelled by the body in 6 sec is

            S' =176.4m

∴h=S –S'

​      =490–176.4

       =313.6m

∴P.E=mgh

=0.1∗9.8∗313.6

=307.3J.